Preventative Repairs?

Reciently, within 5000 miles, my mechanic changed my transmission fluid because i felt that my 1990 Buick LeSabre Limited coupe 3.8 V6 was shifting a little on the hard side. He is a great mechanic and does some of the best work i've ever seen so i dont think he is at fault at all. Now (i think that because i do too much quick accelerating and fast driving) my transmission seems to have a sort of floppy shift or maybe its 'slipping' but the problem is really only noticeable between 1-2 gears. Should i get a full transmission flush, change the fluid again, or just get some additive? I want to solve this problem now so as to not risk the tranny. The car shouldn't have any major tranny problems because i got it with only 59000 miles on from an old lady. She took very good care of it keeping it in her garage every night. Also, my car seems to hesitate when it hasn't been driven for say more than a day. Is this to do with the starter or the spark plugs? I've never had any experience with this stuff so any imput is very greatly apprecieated.

Thanks in advance for all your imput.

David

1990 Buick LeSabre Limited Coupe
3800 Series 3.8 V6 Fuel Injected

Have you checked the front transmission mount?

I have not checked the front transmission mount because i don't know what it is but i'll try to look into it. What am i looking for exactly etc.?

You will be looking between the engine and radiator on the front driver’s side of the engine. You will see a piece of rubber between two metal pieces bolted to the block and frame cross member. You can test it by having someone hold the brake on, (someone you trust), while in drive and bring up the engine RPM to about 1500. If you see a crack between the rubber and the metal pieces, you have a broken mount, By the way, hard acceleration from a stop, is the number one cause of the mount breaking! Come out of the hole easy, and then go to WOT. (Much easier on the mount).